Cllr John O'Donnell (34) was arrested at his home in Co Donegal on Wednesday.

He was taken to Letterkenny Garda Station, where he was questioned about an incident where a man sustained serious injuries at The Grill Nightclub on February 23.

It is understood he strenuously denied that he was involved in any way. The independent councillor was later released with a file being prepared for the Director of Public Prosecutions (DPP).

A garda spokesman said: "Gardaí can confirm that a male was arrested on the 16th December 2015 in relation to an ongoing investigation into an alleged assault which occurred in Letterkenny earlier this year.

"It would be inappropriate for An Garda Síochána to comment further at this stage."

Meanwhile, Mr O'Donnell is expected to make a public appearance in his home village of Kilmacrennan this Saturday. He organises an annual visit by the Coca-Cola Santa truck.

Local newspaper the 'Tirconaill Tribune' reported yesterday that Mr O'Donnell had sought the advice of senior counsel on the RTÉ allegations.

The politician was filmed asking for money in return for helping a fictitious wind farm company set up by the undercover 'RTÉ Investigates' team.

In a letter to fellow county councillors, he said: "I genuinely believed the meeting at issue to be a serious business meeting and had every reason to believe that it could have been of significance for the county, of which I have been very honoured and proud, as a Donegal man, to represent since my election." He apologised for any "misunderstanding" as well as the "perceived" wrongdoing.